TBF, they should stop selling most things OTC. In the current US system that would mean massive additional costs to the consumer, but that is really a policy problem and not a medical one.
Where would you draw the line? Being unable to buy something simple like ibuprofen OTC would (as you point out) mean massive costs for people, and to what benefit? Is there really a huge problem with people overdosing on ibuprofen and suffering permanent damage or death?
And even if there is, would we really expect requiring a prescription to fix that problem? That doesn't seemed to have kept opiates from ruining people's lives.